Powertrain Control Module (Pcm): Notes

The Powertrain Control Module (PCM) is a preprogrammed, triple microprocessor digital computer. For PCM location, see PCM LOCATION table. The PCM controls A/C compressor clutch, air/fuel mixture, charging system, emission control components, idle speed, ignition timing, speed control and some transmission functions. The PCM can adapt it's operation to handle changing operating conditions.

The PCM receives input signals from various sensors and switches. The sensors and switches that provide inputs to PCM are PCM inputs. The PCM controls various engine and vehicle operations through different system components. These components are referred to as PCM outputs. The PCM adjusts fuel system, charging system and ignition timing based on inputs from various sensors and switches.

PCM LOCATION

Application	Location
Cherokee	Left Front Corner Of Engine Compartment
Grand Cherokee	Right Rear Corner Of Engine Compartment, Behind Coolant Tank
Wrangler	Right Rear Corner Of Engine Compartment, Near Battery

NOTE: Components are grouped into 2 categories. The first category covers PCM INPUTS which control or produce voltage signals that are monitored by the PCM. The second category covers PCM OUTPUTS which are components controlled by the PCM.